Pleosporales - CBS - KNAW

Fungal Diversity
(CBS 627.86) was isolated by K. & L. Holm, who had
examined the type specimen of L. nucula (Holm and Holm
1988), the culture of Lophiostoma macrostomum used in
the analysis are unverified (see comment by Zhang et al.
2009b). For the purpose of this monograph we tentatively
maintain Lophiotrema as distinct from Lophiostoma.
Macroventuria Aa, Persoonia 6: 359 (1971).
(Didymellaceae)
Generic description
Habitat terrestrial, saprobic. Ascomata small, solitary, scattered,
or in groups, initially immersed, becoming erumpent, to nearly
superficial, globose to subglobose, roughened with cylindrical
setae erect from apex. Peridium thin, membranous. Hamathecium
of cellular pseudoparaphyses, seems to easily disappear
when mature. Asci bitunicate, somewhat obclavate to fusoid.
Ascospores fusoid with broadly to narrowly rounded ends,
hyaline, 1-septate, constricted at the septum.
Anamorphs reported for genus: none.
Literature: van der Aa 1971; von Arx and Müller 1975;
Barr 1987a.
Type species
Macroventuria wentii Aa, Persoonia 6: 361 (1971). (Fig. 53)
Ascomata 135–180 μm diam., rarely more than 200 μm
diam., solitary, scattered or in groups, initially immersed,
becoming erumpent, to nearly superficial, with basal wall
remaining immersed in host tissue, globose to subglobose,
broadly or narrowly conical, setae erect from the apical region of
the ascomata, cylindrical or tapering to the rounded or pointed
tip, brown, up to 90 μm long, 5–7.5 μm thick (Fig. 53a).
Peridium, 25–35 μm thick, 2-layered, out layer composed of
relatively thick-walled cells of textura angularis, cell wall up to
3 μm thick; inner layer cells with a thinner wall and subhyaline;
near apex cells smaller (Fig. 53a). Hamathecium of cellular
pseudoparaphyses, 1–2 μm thick, evanescing not sure. Asci 75–
93×24–30 μm, 8-spored, without pedicel, bitunicate, somewhat
obclavate to fusoid (Fig. 53b). Ascospores 22–32×8–14 μm, 1–
3 seriate, fusoid with broadly to narrowly rounded ends, hyaline,
1-septate, constricted at the septum, smooth (Fig. 53b) (description
adapted from van der Aa 1971).
Anamorph: none reported.
Material referred: USA, Nevada; Death Valley, plant
litter, F.W. Went, 229, 1970 (CBS 526.71, holotype).
Notes
Morphology
Macroventuria was formally established by van der Aa
(1971) represented by M. anomochaeta and M. wentii based
on its “near-hyaline, 1-septate ascospores, setose ascomata,
and saprobic life style”. Almost all of the above characters
(except the saprobic life style) point this group of fungi to
Venturiaceae. Thus Macroventuria was assigned to this
family as a relatively primitive genus (van der Aa 1971).
Subsequently, von Arx and Müller (1975) assigned Macroventuria
to Pseudosphaeriaceae (Dothideales), and this
proposal was followed by Barr (1987a).
Phylogenetic study
Phylogenetic analysis based on combined SSU rDNA
and LSU rDNA sequences indicated that both of Macroventuria
anomochaeta and M. wentii form a robust clade
with Leptosphaerulina argentinensis (Speg.) J.H. Graham
& Luttr., L. australis, L. trifolii (Rostr.) Petr. and
Platychora ulmi, which appear to share phylogenetic
affinities with the Leptosphaeriaceae and Phaeosphaeriaceae,
but detached from other members of Venturiaceae
and Pleosporaceae (Kodsueb et al. 2006a). In addition,
culture characters also support the close relationship
between Macroventuria and Leptosphaerulina (Barr
1987a). Analysis based on five genes, i.e. SSU, LSU,
RPB1, RPB2 andTEF1, indicated Macroventuria anomochaeta
resides in the well supported clade of Didymellaceae
(Zhang et al. 2009a).
Concluding remarks
The morphological characters, such as small ascomata
and hyaline, 1-septate ascospores all point at Didymellaceae,
thus the familial status of Macroventuria is verified.
Mamillisphaeria K.D. Hyde, S.W. Wong & E.B.G. Jones,
Nova Hedwigia 62: 514 (1996b). (?Melanommataceae)
Generic description
Habitat freshwater, saprobic. Ascomata superficial, scattered
or gregarious, conical, carbonaceous, papillate.
Hamathecium of dense, filliform, trabeculate pseudoparaphyses.
Asci broadly clavate to clavate, with small ocular
chambers and short pedicels. Ascospores of two types, (1):
2-4-seriate, ellipsoid, hyaline, slightly constricted at the
main septum; with apical appendages at each end and
around the ascospore; (2) 1-2-seriate, ellipsoid to fusoid,
brown, with mucilaginous sheath around the ascospore
(Hyde et al. 1996b).
Anamorphs reported for genus: none.
Literature: Hyde et al. 1996a, b.
Type species
Mamillisphaeria dimorphospora K.D. Hyde, S.W. Wong
& E.B.G. Jones, Nova Hedwigia 62: 515 (1996b). (Fig. 54)